Analysis of four microsatellite markers from Mud Crab Scylla serrata revealed that there is high level of genetic diversity within this species. Genetic diversity of S. serrata was calculated using allele diversity, observed heterozygosity, expected heterozygosity (Het-exp), polymorphic information content, gene differentiation and Nei's distance. Mean polymorphic information content value was 0.797, which reflected high level of polymorphism across the loci of S. serrata. The Palau population has the highest genetic diversity (Het-exp=0.871), while the Kosrae population has the lowest genetic diversity (Hetexp=0.806). However, the geographical genetic distance among S. serrata populations from Yab, Chuuk, Pohnpei, Kosrae, and Palau were low (0.20090.3350). These results suggest that despite their wide distribution, S. serrata are no different in geographical genetic diversity within the five sampled locations.